1. The Field of the Invention
The present invention relates to dietary supplements and more particularly to dietary supplements providing ascorbic acid.
2. Background of the Invention
It is well-known that vitamin C is necessary for general well being and good health in humans. Because humans are one of the few animals which lack the biochemical mechanisms to synthesize vitamin C, it must be supplied in the diet in the form of food or supplement. Englard, S. and Steifter, S. "The Biochemical functions of Ascorbic Acid," Ann. Rev. Nutr. 1986; 365-406. Deficiencies of vitamin C lead to many health complications, such as (a) abnormal bleeding in the skin, mucous membranes, internal organs, and muscles, due to impaired capillary integrity with subcutaneous hemorrhages, (b) edema, (c) joint pain, (d) anorexia, (e) anemias, (f) impaired wound healing, as well as resulting in generally poor health. See Mahan, L. K. and Arlin, M. T. 1992, KRAUSES'S FOOD, NUTRITION AND DIET THERAPY 8th ed. Philadelphia, W. B. Sauders; Anderson, W. A. D., 1971 and PATHOLOGY 6th ed. St. Louis, The C. V. Mosby Company.
Vitamin C deficiencies in children can result in joint swelling, arrested skeletal development, tenderness and swelling of joints, impaired wound healing, anemia and inadequate tooth development. See Anderson, W. A. D., 1971. PATHOLOGY 6th ed. St. Louis: The C. V. Mosby Company. Diseases like scurvy, which is characterized by sore and spongy gums, can be prevented with vitamin C supplementation. Except where inborn errors of metabolism such as cystinuria, oxalosis, and hyperuricemia are present, it is accepted wisdom that vitamin C can be taken in megadoses without toxic side effects. See Stanbury, J. B., Wyngaarden, J. B., Fredrickson, D. S., 1972, THE METABOLIC BASIS OF INHERITED DISEASE 3rd ed. McGraw Hill.
Vitamin C has many different mechanisms by which it offers a protective and beneficial effect. See Anderson, R., 1981 ASCORBIC ACID AND IMMUNE FUNCTIONS: MECHANISM OF IMMUNOSTIMULATION IN VITAMIN C (ASCORBIC ACID) ed. by Counsell, J. N. and Hornig, D. H. 249-272, New Jersey, Applied Science Publishers; Block, G. "Vitamin C and Cancer Prevention: The Epidemiologic Evidence" Am. J. Clin. Nutr. 1991, 53:270S-82S; Linder, M. C. 1991 NUTRITIONAL BIOCHEMISTRY AND METABOLISM WITH CLINICAL APPLICATIONS 2d ed. New York, Elsever.
Clinical evidence has demonstrated that ascorbic acid participates in the hydroxylation reactions associated with cholesterol metabolism. Ginter, E. "Cholesterol: Vitamin C Controls Its Transformation to Bile Acids" Science 1973, 179:702-704. Cholesterol is produced in the body by certain organ metabolism, as well as being acquired by dietary intake. The human body rids itself of excess cholesterol either in its unchanged form, excreted as waste, or through a series of reactions by which the cholesterol is transformed into bile acids in the liver and later excreted as waste. Studies have shown that a deficiency in ascorbic acid in guinea pigs results in an accumulation of cholesterol in the blood plasma. Id. It has been theorized that with a low concentration of vitamin C, cholesterol cannot be converted into bile acids in the liver. The accumulation of cholesterol in blood plasma can lead to undesirable atheromatous changes in the blood vessels.
Another matter related to metabolism of cholesterol and vitamin C deficiency involves the cytochrome P-450 and cytochrome P-450 reductase. Id. These cytochromes are involved with the C7-hydroxylation of cholesterol. Both the levels of cytochrome P-450 and cytochrome B in the liver decreases 24 hours after depletion of vitamin C from the diet. A low count of cytochrome P-450 is a very sensitive indicator of early scurvy.
Another beneficial effect of vitamin C is the elevation of glutathione, a component of red blood cells. Glutathione is an important antioxidant defense mechanism. Reduced glutathione promotes the antioxidant properties of vitamin C and E. Low plasma levels of reduced glutathione is associated with depressed immunity. Studies have shown that vitamin C supplementation (e.g., 500 mg/day) increases plasma concentrations of glutathione. Johnston, C. S. et al. "Vitamin C Elevates Red Blood Cell Glutathione in Healthy Adults" Am. J. Clin. Nutr. 1993, 58:103-105.
It has also been postulated that vitamin C has highly important functions in some hydroxylation reactions. Englard, S. and Steifter, S. "The Biochemical functions of Ascorbic Acid," Ann. Rev. Nutr 1986, 6:365-406 Such reactions include those important to human well being including the formation of epinephrine from DOPA and the hydroxylation of aromatic compounds in the liver.
Further beneficial effects of vitamin C have been recognized in studies on fibroblast cell cultures which indicate that the hydroxylation reaction of proline and lysine in protocollagen occurs in the presence of ascorbic acid. Id. Without ascorbic acid, collagen forms abnormally and becomes weak, which increases the chance of hemorrhaging and slow healing. The enzyme hydroxylase which forms the bonds between proline and hydroxylysine of collagen requires oxygen, a ferrous ion, and a reductant. While ascorbic acid is not the only reductant used for the formation of the collagen bonds between proline and hydroxylysine, it is, however, the most effective compound for the reaction.
It is well-known that smoking is a great hazard to a person's health because it causes a wide variety of metabolic changes. In the case of vitamin C, smoking lowers the vitamin C levels in blood plasma. It is believed that the nicotine in smoke releases catecholamine from the adrenal glands in their active circulation form. When the compounds are in their active form, their biosynthesis consumes ascorbic acid.
Perhaps most notable of the beneficial effects of vitamin C is the large role it plays in supporting the function of the human immune system. As a therapeutic agent, ascorbic acid has been shown to be useful for certain types of cancer treatments. Indeed, there is consistent epidemiological evidence that supports the concept that ascorbic acid provides a protective effect from a variety of human and animal tumors. Vitamin C is postulated to stimulate the human immune system by enhancing interferon synthesis and lymphocyte activity, particularly the class of lymphocyte referred to as natural killer (NK) cells. Sigel, B. V. & Morton, J. I. "Vitamin C and Immunity: Natural Killer (NK) cell factor" Int. J. Vitamin & Nutrition Res. 1983, 53:179-183; Lovzova, E., Savary, C. A., & Heberman, R. B. "Induction of NK cells activity against fresh human leukemia in culture with interlukin 2" J. Immunology 1987, 138:2718-2727. Natural killer cells are lymphocytes that spontaneously kill tumor or virus-infected cells. Decreased numbers of circulating NK cells have been linked to the development and progression of various immunodeficiencies, viral infections, AIDS, and cancer.
Moreover, vitamin C is believed to provide further benefits by acting as an antioxidant aiding the immune system by reducing the amount of free radical damage that can occur as a result of normal body metabolism as well as from exogenous sources (e.g., pollution). Free radicals have been shown to play a role in tumorigenesis by causing lipid peroxidation and damage to DNA.